1. Field of the Invention
The invention relates to a scanhead and in particular, to an ultrasonic scanhead.
2. Description of the Prior Art
A transducer of an ultrasonic scanhead is capable of transforming electrical signals into ultrasonic impulse signals and transmitting the ultrasonic impulse signals. When the transducer of the ultrasonic scanhead attaches to a human skin, the transducer transmits the ultrasonic impulse signals into the human body. Because different kinds of body tissues reflect the ultrasonic impulse signals transmitted into the human body in different degrees such that an image having characteristic information is received by the transducer. The transducer further transforms the received ultrasonic impulse signals into electrical signals and transmits the electrical signals into a computer for further calculation. By means of the abovementioned procedures, related image is displayed on a display device of the computer.
A conventional art of the ultrasonic scanhead has been disclosed in U.S. Pat. No. 7,255,678. However, in the conventional art, an encoder, and a transducer are located at opposite ends of a pivot of the ultrasonic scanhead, so the size of the conventional ultrasonic scanhead is relatively large. In addition, in the conventional art, a torque motor of the ultrasonic scanhead drives the pivot to rotate back and forth. However, during operation of the torque motor, shortcomings such as stagnation behavior, force ripple, and cogging force arise. Moreover, the transducer of the conventional ultrasonic scanhead can not be replaced. For the abovementioned reasons, it is necessary to improve the conventional ultrasonic scanhead.